What happened
On June 17, 2018, a private flight involving an Alexander Schleicher ASW-24 glider, registration D-6024, began at the Fuentemilanos Aerodrome in Segovia, Spain. The flight commenced at 16:24 local time via a tow operation that reached an altitude of 600 meters. Utilizing strong thermal currents, the pilot successfully climbed to 1,600 meters and proceeded southwest toward Aldeavieja, following the N-110 highway.
During the return leg of the flight, the pilot experienced a rapid loss of altitude caused by increasing northeast winds. As the aircraft's ability to reach the home aerodrome diminished, the pilot notified Fuentemilanos via radio of the intention to perform an off-field landing. The pilot selected a wheat field located approximately 5 km from the aerodrome, situated to the right of the N-11 of the highway, intending to land into the wind toward the northeast.
During the landing roll, the left wingtip struck an obstacle—a tree stump partially hidden within the crop—and a slight rise in the terrain. This impact caused a violent leftward yaw, leading to significant structural damage. The pilot, who was uninjured, was able to exit the aircraft and communicate their position via telephone.
The investigation
The investigation examined the aircraft's structural integrity, the meteorological conditions, and the pilot's decision-making process. Investigators analyzed the damage to the Alexander Schlelauncher ASW-24, noting impact marks on the left wingtip and significant deformation in the wing root and fuselage. The investigation also reviewed local weather data, which confirmed that while thermal conditions were initially favorable, wind intensity increased toward the end of the afternoon, contributing to the pilot's descent rate.
Findings
- The pilot was flying with valid licenses and medical certification.
- The aircraft was airworthy and all documentation was up to date.
- The pilot's decision to fly away from the aerodrome was influenced by the favorable initial thermal conditions.
- The increasing northeast wind reduced the aircraft's ground speed and prevented a return to the aerodrome.
- The pilot performed the landing without having clear visual contact with the ground surface, failing to detect the tree stump and terrain undulations hidden by the wheat crop.
- The impact of the left wingtip with the stump caused the primary structural failures, including damage to the wing root, fuselage cracks behind the cockpit, and the breakage of the right horizontal stabilizer.